1232772 玖、發明說明： 【發明所屬之技術領域】 本發明係關於一種電透析裝置節省酸用量之方法，係將陽極 極室產生的酸性極水迴流注入各濃室之入口端，藉此降低濃水端 的pH值，防止發生沈澱或結垢現象，節省額外添加的酸用量。 【先前技術】 特殊分離系統的技術著重於薄膜分離技術的開發與應用，薄 膜分離應用具有一個共同的特性，就是所有的分離流程皆需在薄 膜存在的狀態下來完成，薄膜是兩種物質間具有選擇性的障礙， 其中視分離物種的粒徑而有適用的應用技術。目前薄膜分離技術 包括有利用電位差當成驅動力來進行分離的電透析分離技術，利 用溶液濃度差進行分離的擴散透析與壓力差進行分離的逆滲 透、壓力透析等技術，這些技術的原理均是利用薄膜透析設備在 電位差、濃度差、壓力差與溫度差的驅動力驅使下，經由不同薄 膜孔徑大小與離子選擇性，進行透析作用而達成分離目的。 使用離子交換膜於透析的應用領域有：1.擴散透·析：其係應 用於非鐵電解液精製、金屬鹽類回收、鋁陽極處理浴、鋼鐵酸洗 浴、鋁箔電解蝕刻金屬表面安定化等；2.壓力透析：應用於鋁陽 極處理、金屬鹽類濃縮回收、有機物純化及酸性廢水回收等；3. 電透析··應用於食鹽製造、放射性廢液處理、電鍍廢液中回收有 價金屬、鍋爐用水前處理、藥品、食品脫鹽及果汁去酸等。 在技術層次上擴散透析應用到離子交換膜的選擇性及濃度 差等兩項因子，電透析則除了原有的質傳與流力兩項理論外，更 增加了電化學的原理，使得電透析的技術應用上引用了相當多的 經驗式；加上特殊的離子交換膜與多重模組的開發，使得擴散透 析與隔膜電解的應用也越來受到重視，設計分離系統、測試分離 效率與個別技術的整合運用能力，可以針對各個不同的應用現況 1232772 做最適的設計與生產流程規劃。 一 電透析（electrodialysis，ED)處理技術係利用不同特性的 =犋對水中的離子做一分離選擇，水中離子的移動則是靠正負直 <龟來當吸引的驅動力，而倒極式電透析（eiectr〇cjjalysis 「eversal , EDR)是將電透析處理技術作進一步修正，乃利用直 流電正負極和内部導流的切換來延長薄膜使用裝置。第一圖所示 為一般電透析操作原理的示意圖，電透析設備通電操作時，兩端 的電極表面上還有電化學反應發生，在陽極會反應產生氧氣和 H，極水呈酸性。而在陰極產生氫氣與〇|«|-，極水呈鹼性。靠近 電極的隔室（極室）需要通入極水，極水可為原水或淡水，以便 不斷排出電透析過程在極室產生的電解反應產物，其中陰極室和 陽極室的流出液中，分別含有鹼或酸和氣體。電透析用於脫鹽原 理則是利用陽離子只能穿透陽離子交換膜，而陰離子只穿透陰離 子交換膜的特性，在外加直流電場的作用下，水中的陰離子移向 陽極，陽離子移向陰極，最後得到淡水及濃水，達到淡化除鹽的 目的。 ‘電透析（ED)及倒極式電透析（EDR)的設計視處理需求及 原水水質而定，主要構成為膜組（membrane stacks)、薄膜 (membrane)、電極（electrodes)及隔間（spacers)，於膜的一端设 置陽極與陰極，在框的上緣、下緣開設溶液流通的通路孔，通路 孔在透析槽裝配、重疊時彼此形成液路，這些通路孔交替以細流 路連通液室。進流經由此設計，分為淡水（dllUte)與濃水 (concentrate)經不同室離開，各室以陽離子和陰離子交換膜隔 開，室間設間隔物，使液室保持一定間隙，並有助於液流的混合。 而隨設備通電操作過程，在濃水區域因為濃縮的效果，常常 會發生碳酸鈣（CaC03)或硫酸鈣（CaS〇4)沈澱造成堵塞，在 一般操作控制常利用額外添加酸以降低PH值，這對 < 透析裝置 1232772 應用於大量的廢水回收、硬水軟化、飲用水或地下水脫鹽或海水 淡化，無疑是筆額外的支出。 【發明内容】 有鑑於習知技術的缺失，本發明提供之節省酸用量之電透析 裝置及方法，係利用電透析設備通電操作時，陽極極室内反應產 生氧氣和H+使極水呈酸性，將陽極極水以接管方式導至濃水入 口，可降低濃水之pH值，防止碳酸鈣（CaC〇3)或硫酸鈣（CaS〇4) 沈澱造成堵塞，節省額外添加酸的用量。 本發明之目的係提供一種節省酸用量之電透析裝置，其係包 含：一工作槽；至少一組離子交換膜；一陽極極室；一陰極極室； 一陰極，係設於前述陰極極室内用以與負電連接；一陽極，係設 於前述陽極極室内用以與正電連接，前述介於陰極極室與陽極極 室間，由離子交換膜區隔依序形成淡室及濃室；其特徵係為：前 述陽極極室係藉由一輸送管線與濃室連接，以將陽極極室產生的 酸性極水導至濃室，用以降低濃室中濃水之pH值，避免濃室產 生沈澱及/或結垢現象。 前述電透析裝置係為固定電極電性之電透析裝置或正負極 與内部導流可切換之倒極式電透析裝置。 前述至少一組離子交換膜係由相同數目之陰離子交換膜及 陽離子交換膜於前述工作槽中間隔排列。 前述陰極極室係由陽離子交換膜與工作槽槽壁構成；前述陽 極極室係由陰離子交換膜與工作槽槽壁構成，且前述陰極極室及 陽極極室係分別位於工作槽之兩端。 前述陽極極室與濃室之連接方式係藉由一輸送管線將陽極 極室之極水出口端與濃室之濃水注入口端相連接。 前述濃室係連接一組濃水輸送管線進行濃水注入與輸出。 前述淡室係連接一原水輸送管線進行原水注入。 1232772 前述淡室係連接一淡水輸送管線進行淡水輸出。 前述陰極極室係連接一組陰極極水輸送管線進行陰極極水 之注入與輸出。 前述陽極極室係連接一組陽極極水注入管線及輸出管線進 行陽極極水之注入與輸出。 本發明之另一目的係提供一種節省電透析裝置酸用量之方 法，其特徵係將陽極極室產生的酸性極水直接或間接導至濃室之 濃水中，藉由電透析過程中，陽極產生氧氣和氫離子使極水呈酸 性，將此酸性陽極極水導至濃室之濃水中，藉此降低濃水之pH 值，避免濃室產生沈澱及/或結垢現象。藉由上述方法可節省額外 添加酸的量。 利用本發明之節省酸用量之電透析裝置或方法，仍可視情況 進一步添加酸以增加其降低濃水pH值之效果，並不受限制。 前述原水係可為廢水、硬水、飲用水、地下水、半鹽水或海 水0 前述極水係可為原水或淡水。 本發明之再一目的係提供一種節省電透析裝置酸用量之方 法，係藉由本發明之電透析裝置達成。 1 本發明提供之節省酸用量之電透析裝置及方法，係將陽極極 室内反應生成酸性極水，以接管方式將陽極極水導至濃水注入各 濃室之入口端，可降低濃水之pH值，防止碳酸鈣（CaC〇3)或 硫酸鈣（CaS〇4)沈澱造成堵塞，節省額外添加酸的用量。 【實施方式】 如第二圖所示之節省酸用量之電透析裝置1，其組成元件包 含工作槽2、堆疊置於工作槽2中之陽離子交換膜3及陰離子交 換膜4，其中堆疊之離子交換膜一側之陽離子交換膜3與工作槽 壁形成陰極極室5，堆疊之離子交換膜另一側之陰離子交換膜4 1232772 與工作槽壁形成陽極極室6，陰極極室5中具有一陰極7與負電 相接，陽極極室6中具有一陽極8與正電相接，而介於陰極極室 5與陽極極室6間，由離子交換膜區隔形成的區域則由工作槽2 兩側向中央依序形成複數個淡室9及濃室10。 濃室10係連接一組濃水輸送管線13進行濃水的注入與輸 出，淡室9係連接一原水輸送管線11進行原水注入及一淡水輸 送管線12進行淡水輸出。陰極極室5係利用一組陰極極水輸送 管線14進行陰極極水之注入與輸出，而陽極極室6係連接一組 陽極極水注入管線15及陽極極水輸出管線16進行陽極極水之注 入與輸出。 陽極極室6與濃室10之濃水注入口係接管連接，藉此利用 此輸送管線16將陽極極室6產生的酸性極水導至各濃室10之入 口端，注入濃水中。 利用前述電透析裝置1節省酸用量之方法，係將陽極極室6 產生的酸性極水直接接管至濃室10之濃水注入口，當電透析裝 置1通電操作時，淡室9中原水的陽離子及陰離子分別通過陽離 子交換膜3及陰離子交換膜4進入濃室10,陽極8則會產生氧氣 和氫離子使極水呈酸性，將此酸性陽極極水導至各'濃室10入口 端，分別注入濃水中，可降低濃水之酸驗值，避免沉殿及/或結垢 現象產生，進而達到節省額外添加酸的用量。 前述原水係可為廢水、硬水、飲用水、地下水、半鹽水或海 水。前述極水係可為原水或淡水。 •以下實施例係用於進一步了解本發明之優點，並非用於限制 本發明之申請專利範圍。 實施例利用節省酸用量之電透析裝置進行自來水去離子反應 本實施例係使用本發明之節省酸用量之電透析裝置，該電透 析裝置中之陰離子交換膜及陽離子交換膜共有二十對膜，並以自 !0 1232772 來水為原水進行電透析實驗。當實驗組通電操作時，於淡水室中 定量注入300ml/min自來水，操作電壓設定在20V，電流約0.1 A。 為進行原水、淡水及濃水的輸送，濃室係連接一組濃水輸送管線 進行濃水的注入與輸出，淡室係連接一原水輸送管線進行原水注 入及一淡水輸送管線進行淡水輸出。 陰極極室及陽極極室則利用一組陰極極水輸送管線進行陰 極極水之注入與輸出，而與一組陽極極水注入管線及陽極極水輸 出管線進行陽極極水之注入與輸出。濃水、陽極水、陰極水等皆 循環操作。 為達到利用酸性之I%極極水降低濃水p Η值之目的，本發明 係抽取陽極水以50ml/min流量注入濃水，並且每半小時以自來 水補充被抽取之陽極極水。實驗結果如表―，由結果可看出濃水 pH值已被控制於8.5以下。pH值的變化與原水之成分有關，但 不淪原水之成分為何，利用酸性之陽極極水可降低濃水之pH值， 使結垢現象不易發生。 表一量電之度電ί/Γ置通電操作時極1232772 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to a method for saving the amount of acid in an electrodialysis device. The acidic water produced by the anode electrode chamber is refluxed into the inlet end of each thick chamber, thereby reducing the concentration. The pH value at the water end prevents precipitation or scaling and saves the amount of additional acid. [Previous technology] The technology of special separation system focuses on the development and application of membrane separation technology. Membrane separation application has a common characteristic, that is, all separation processes must be completed in the state of the existence of the membrane. Obstacles of selectivity, among which there are applicable techniques depending on the particle size of the separated species. Current membrane separation technologies include electrodialysis separation technology that uses potential difference as a driving force for separation, diffusion dialysis using solution concentration difference for separation, pressure dialysis for reverse osmosis, pressure dialysis, and other technologies. The principle of these technologies is to use Membrane dialysis equipment is driven by the driving force of potential difference, concentration difference, pressure difference, and temperature difference to achieve the purpose of separation through different membrane pore sizes and ion selectivity. The application fields of ion exchange membranes for dialysis are: 1. Diffusion and analysis: it is used in the purification of non-ferrous electrolytes, recovery of metal salts, aluminum anode treatment baths, steel acid baths, aluminum foil electrolytic etching, metal surface stabilization, etc. 2. Pressure dialysis: applied to aluminum anode treatment, metal salt concentration recovery, organic matter purification, and acidic wastewater recovery; etc. 3. Electrodialysis ·· Applied to salt manufacturing, radioactive waste liquid treatment, electroplating waste liquid recovery of valuable metals, Boiler water treatment, medicine, food desalination and juice deacidification. At the technical level, diffusion dialysis is applied to two factors, such as the selectivity and concentration difference of ion exchange membranes. In addition to the original two theories of mass transfer and flow force, electrodialysis has added the principle of electrochemistry to make electrodialysis. Quite a lot of empirical formulas are cited in the application of the technology; coupled with the development of special ion exchange membranes and multiple modules, the application of diffusion dialysis and diaphragm electrolysis has become more and more important. Designing separation systems, testing separation efficiency and individual technologies The ability to integrate and use can make the most appropriate design and production process planning for different application conditions 1232772. An electrodialysis (ED) treatment technology uses different characteristics of 犋 to make a separation selection of ions in water, and the movement of ions in water is driven by the positive and negative straight and tortoises as the driving force of attraction. Dialysis (eiectrócjjalysis "eversal (EDR)" is a further modification of the electrodialysis treatment technology, which uses the switching of DC positive and negative electrodes and internal diversion to extend the device for membrane use. The first figure shows a schematic diagram of the general principle of electrodialysis operation When the electrodialysis equipment is powered on, electrochemical reactions occur on the electrode surfaces at both ends. The anode will react to produce oxygen and H, and the polar water is acidic. The cathode produces hydrogen and 〇 | «|-, and the polar water is alkaline. The compartment (electrode chamber) near the electrode needs to pass into polar water, which can be raw water or fresh water, in order to continuously discharge the electrolytic reaction products produced in the electrode chamber during the electrodialysis process, in which the effluent from the cathode and anode chambers , Respectively containing alkali or acid and gas. The principle of electrodialysis for desalination is to use cations to penetrate only the cation exchange membrane, and anions to penetrate only the anion exchange. Under the action of an external DC electric field, the anions in the water move to the anode and the cations move to the cathode, and finally get fresh water and concentrated water to achieve the purpose of desalination and desalination. 'Electrodialysis (ED) and inverted polar electrodialysis ( The design of EDR depends on the processing requirements and the quality of the raw water. It is mainly composed of membrane stacks, membranes, electrodes, and spacers. An anode and a cathode are set at one end of the membrane. The upper and lower edges of the openings are provided with solution flow passage holes. The passage holes form a liquid path with each other when the dialysis tank is assembled and overlapped. These passage holes alternately connect the liquid chamber with a thin flow path. The inflow is divided into fresh water (dllUte) through this design. It is separated from concentrated water through different chambers, and each chamber is separated by a cation and anion exchange membrane. Spacers are set between the chambers to maintain a certain gap in the liquid chamber and facilitate the mixing of the liquid flow. The operation process with the equipment power on In the concentrated water area, due to the effect of concentration, calcium carbonate (CaC03) or calcium sulfate (CaS04) precipitation often occurs and blockage is caused. In general operation control, additional acid is often added to reduce Low PH value, this pair of dialysis device 1232772 is applied to a large amount of wastewater recovery, hard water softening, drinking water or groundwater desalination or seawater desalination, which is undoubtedly an extra expense. [Summary of the Invention] In view of the lack of conventional technology, the present The invention provides an electrodialysis device and method for saving acid consumption. When the electrodialysis equipment is powered on and operated, the anode chamber reacts to generate oxygen and H + to make the polar water acidic. Decrease the pH value of concentrated water, prevent clogging caused by precipitation of calcium carbonate (CaC〇3) or calcium sulfate (CaS〇4), and save the amount of additional acid. The object of the present invention is to provide an electrodialysis device that saves the amount of acid. The system comprises: a working tank; at least one set of ion exchange membranes; an anode electrode chamber; a cathode electrode chamber; a cathode electrode arranged in the aforementioned cathode electrode chamber for connection with negative electricity; an anode electrode arranged in the aforementioned anode electrode chamber Used for positive electrical connection, the aforementioned is located between the cathode and anode chambers, and the light exchange chamber and the thick chamber are sequentially formed by the ion exchange membrane partition; its characteristics are as follows: The electrode chamber is connected to the thick chamber through a transmission line to guide the acidic water produced in the anode electrode chamber to the thick chamber to reduce the pH value of the concentrated water in the thick chamber and avoid precipitation and / or scaling in the thick chamber. phenomenon. The aforementioned electrodialysis device is an electrodialysis device with fixed electrode electrical properties or an inverted polar electrodialysis device with switchable positive and negative electrodes and internal diversion. The at least one set of the ion exchange membranes are arranged at equal intervals in the working tank by the same number of anion exchange membranes and cation exchange membranes. The cathode chamber is composed of a cation exchange membrane and a working tank wall; the anode chamber is composed of an anion exchange membrane and a working tank wall, and the cathode and anode chambers are located at both ends of the working tank, respectively. The connection method between the anode chamber and the thick chamber is to connect the anode water outlet end of the anode chamber and the thick water injection end of the thick chamber through a transmission line. The aforementioned thick chamber is connected to a set of concentrated water delivery pipelines for the injection and output of concentrated water. The fresh room is connected to a raw water delivery pipeline for raw water injection. 1232772 The aforementioned fresh room is connected to a fresh water delivery pipeline for fresh water output. The aforesaid cathode electrode chamber is connected to a set of cathode electrode water delivery pipelines for cathode electrode water injection and output. The anode chamber is connected with a set of anode water injection pipeline and output pipeline for anode water injection and output. Another object of the present invention is to provide a method for saving the amount of acid in an electrodialysis device, which is characterized in that the acidic polar water generated in the anode electrode chamber is directly or indirectly led to the concentrated water in the concentrated chamber. Oxygen and hydrogen ions make the polar water acidic, and this acidic anode polar water is conducted to the concentrated water in the thick chamber, thereby lowering the pH value of the concentrated water and avoiding precipitation and / or scaling in the thick chamber. By the above method, the amount of additional acid can be saved. By using the electrodialysis device or method for saving acid amount of the present invention, it is still possible to further add acid to increase the effect of lowering the pH value of concentrated water according to the circumstances, without limitation. The aforementioned raw water system may be wastewater, hard water, drinking water, groundwater, semi-brine or sea water. The aforementioned polar water system may be raw water or fresh water. Yet another object of the present invention is to provide a method for saving the amount of acid in an electrodialysis device, which is achieved by the electrodialysis device of the present invention. 1 The electrodialysis device and method for saving acid consumption provided by the present invention, which reacts the anode electrode chamber to generate acidic electrode water, and guides the anode electrode water to the inlet end of each concentrated chamber in a takeover manner, which can reduce the concentration of concentrated water. pH value, to prevent calcium carbonate (CaCO3) or calcium sulfate (CaSO4) from causing clogging and save the amount of additional acid. [Embodiment] As shown in the second figure, the electrodialysis device 1 for saving acid consumption includes a working tank 2, a cation exchange membrane 3 and an anion exchange membrane 4 stacked in the working tank 2, and the stacked ions The cation exchange membrane 3 on one side of the exchange membrane forms the cathode chamber 5 with the working tank wall, and the anion exchange membrane 4 1232772 on the other side of the stacked ion exchange membrane forms the anode chamber 6 with the working tank wall. The cathode chamber 5 has a The cathode 7 is connected to the negative electricity, and the anode electrode chamber 6 has an anode 8 connected to the positive electricity, and is interposed between the cathode electrode chamber 5 and the anode electrode chamber 6, and the area formed by the ion exchange membrane is divided by the working tank 2. A plurality of light chambers 9 and thick chambers 10 are sequentially formed toward the center from both sides. The thick room 10 is connected to a set of concentrated water delivery pipelines 13 for injecting and outputting concentrated water, and the fresh room 9 is connected to a raw water delivery pipeline 11 for raw water injection and a fresh water delivery pipeline 12 for fresh water output. The cathode compartment 5 uses a set of cathode water delivery lines 14 for the injection and output of cathode water, while the anode compartment 6 connects a set of anode water injection lines 15 and the anode water output line 16 for anode water Injection and output. The anode electrode chamber 6 is connected to the concentrated water injection port of the thickened chamber 10, whereby the acidic water generated by the anode electrode chamber 6 is guided to the inlet end of each thickened chamber 10 by this transport line 16 and injected into the concentrated water. The method of using the aforementioned electrodialysis device 1 to save the amount of acid is to directly take the acidic polar water generated in the anode electrode chamber 6 to the concentrated water injection port of the thick chamber 10. When the electrodialysis device 1 is powered on and operated, the raw water in the fresh chamber 9 The cations and anions enter the concentration chamber 10 through the cation exchange membrane 3 and the anion exchange membrane 4, respectively. The anode 8 will generate oxygen and hydrogen ions to make the polar water acidic. This acidic anode polar water will be led to the entrance end of each of the thick chambers. Separate injection into concentrated water can reduce the acid test value of concentrated water, avoid the phenomenon of sinking and / or scaling, and thus save the amount of additional acid. The aforementioned raw water system may be wastewater, hard water, drinking water, groundwater, semi-salt water or sea water. The polar water system may be raw water or fresh water. • The following examples are used to further understand the advantages of the present invention, and are not intended to limit the scope of patent application of the present invention. Example: Deionization of tap water using an electrodialysis device that saves acid usage. This example uses the electrodialysis device that saves acid consumption according to the present invention. The anion exchange membrane and cation exchange membrane in the electrodialysis device have twenty pairs of membranes. The electrodialysis experiment was performed using tap water from! 0 1232772 as raw water. When the experimental group was powered on, tap water of 300ml / min was metered into the freshwater chamber at a fixed volume, the operating voltage was set at 20V, and the current was about 0.1 A. In order to transport raw water, fresh water and concentrated water, the thick room is connected to a set of concentrated water delivery pipelines for the injection and output of concentrated water, and the fresh room is connected to a raw water delivery pipeline for raw water injection and a fresh water delivery pipeline for fresh water output. The cathode and anode chambers use a set of cathode water delivery pipelines for the injection and output of cathode water, and a set of anode water injection pipelines and anode water output pipelines for the injection and output of anode water. Concentrated water, anode water, cathode water, etc. all operate cyclically. In order to achieve the purpose of reducing the p 水 value of concentrated water by using acidic I% polar water, the present invention draws anode water into the concentrated water at a flow rate of 50 ml / min, and supplements the extracted anode water with tap water every half an hour. The experimental results are shown in Table-. From the results, it can be seen that the pH value of concentrated water has been controlled below 8.5. The change in pH value is related to the composition of the raw water, but it does not degrade the composition of the raw water. The use of acidic anode water can reduce the pH value of concentrated water, making scaling difficult to occur. Table 1 Measure of electricity
為比較陽極極水注人濃切降m ΡΗ值之效益，另一對 照組之操作條件都與實驗組相π ^ 叫’但是並不抽取陽極極水注入濃 水中，觀察陰極極水與陽極極火从 π L + 水的pH值，其結果如表二，隨著 刼作時間增加，陰極極水愈驗， 而％極極水愈酸，而濃水pH值 1232772 也隨著時間而增加。 表二、對照組：未抽取陽極極水注入濃水之電透析裝置通電操作 時極水、濃水及淡水之ρ Η值及導電度變化 時間 P] Η 導電度< :ms/cm) (小時） 陽極極水 陰極極水 濃水 淡水 陽極極水 陰極極水 濃水 淡水 0 7.28 7.65 7.67 7.71 0.403 0.383 0.497 0.458 1 7.09 9.67 8.42 6.20 0.325 0.397 2.010 0.071 2 6.03 10.28 8.71 6.11 0.257 0.369 2.740 0.071 3 3.75 10.47 8.81 5.82 0.267 0.453 3.460 0.069 4 3.35 11.07 8.88 5.62 0.259 0.497 4.010 0.068 綜上所述，本發明之節省酸用量之電透析裝置，係利用陽極 極室產生之酸性極水接管至濃水輸送管線，降低濃水pH值以防 止結垢，除有利於電透析設備的維護與水回收率外，更重要的係 可藉此達到節省酸用量之目的，降低操作成本。 雖然本發明已以實施例揭露如上，然其並非用以限定本發 明，任何熟悉此技藝者，在不脫離本發明之精神和範圍内，當可 作各種之更動與潤飾，因此，本發明之保護範圍，當視後附之申 請專利範圍所界定者為準。 η 1232772 【圖式簡單說明】 第一圖係為電透析作用之原理示意圖。 第二圖係為本發明之節省酸用量之電透析裝置示意圖。 【主要元件符號對照說明】 1…節省酸用量之電透析裝置 2…工作槽 3…陽離子交換膜 4…陰離子交換膜 5…陰極極室 6…陽極極室 7…陰極 8…陽極 9…淡室 10…濃室 11…原水輸送管線 12…淡水輸送管線 13…濃水輸送管線 14…陰極極水輸送管線 15…陽極極水注入管線 16…陽極極水輸出管線In order to compare the benefits of lowering the mPΗ value by injecting the anode electrode water, the operating conditions of the other control group are similar to those of the experimental group π ^, but the anode electrode water is not drawn into the concentrated water, and the cathode electrode water and the anode electrode are observed. The pH of the fire is from π L + water. The results are shown in Table 2. As the operation time increases, the cathode electrode water becomes heavier, and the% electrode water becomes more acidic, and the concentrated water pH value 1232772 also increases with time. Table 2: Control group: The electrodialysis device that does not extract anode water and inject concentrated water When the power is on, the ρ Η value and conductivity change time of polar water, concentrated water and fresh water P] Η Conductivity <: ms / cm) ( Hours) anode water cathode water concentrated water fresh water anode water cathode water concentrated fresh water 0 7.28 7.65 7.67 7.71 0.403 0.383 0.497 0.458 1 7.09 9.67 8.42 6.20 0.325 0.397 2.010 0.071 2 6.03 10.28 8.71 6.11 0.257 0.369 2.740 0.071 3 3.75 10.47 8.81 5.82 0.267 0.453 3.460 0.069 4 3.35 11.07 8.88 5.62 0.259 0.497 4.010 0.068 In summary, the electrodialysis device of the present invention that saves acid usage is based on the use of acidic polar water generated in the anode electrode chamber to take over to the concentrated water delivery pipeline to reduce the concentration. The pH value of water to prevent scaling, in addition to being beneficial to the maintenance of the electrodialysis equipment and the water recovery rate, the more important thing is that it can achieve the purpose of saving acid consumption and reducing operating costs. Although the present invention has been disclosed as above by way of example, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the attached patent application. η 1232772 [Schematic explanation] The first diagram is a schematic diagram of the principle of electrodialysis. The second figure is a schematic diagram of an electrodialysis device for saving acid consumption according to the present invention. [Comparison explanation of main component symbols] 1 ... Electrodialysis device that saves acid usage 2 ... Working tank 3 ... Cation exchange membrane 4 ... Anion exchange membrane 5 ... Cathode chamber 6 ... Anode chamber 7 ... Cathode 8 ... Anode 9 ... Fade chamber 10 ... concentrated chamber 11 ... raw water delivery line 12 ... fresh water delivery line 13 ... concentrated water delivery line 14 ... cathode water delivery line 15 ... anode water injection line 16 ... anode water output line